using System;
using System.Text;
using FileHelpers.Helpers;

namespace FileHelpers.Options
{
    /// <summary>Class used to pass information to the <see cref="FileHelpers.Dynamic.CsvClassBuilder"/> and the <see cref="CsvEngine"/></summary>
    public sealed class CsvOptions
    {
        /// <summary>Create a CSV Wrapper using the specified number of fields.</summary>
        /// <param name="className">The name of the record class</param>
        /// <param name="delimiter">The delimiter for each field</param>
        /// <param name="numberOfFields">The number of fields of each record</param>
        public CsvOptions(string className, char delimiter, int numberOfFields)
            : this(className, delimiter, numberOfFields, 1) {}

        /// <summary>Create a CSV Wrapper using the specified number of fields.</summary>
        /// <param name="className">The name of the record class</param>
        /// <param name="delimiter">The delimiter for each field</param>
        /// <param name="numberOfFields">The number of fields of each record</param>
        /// <param name="headerLines">The number of lines to use as header</param>
        public CsvOptions(string className, char delimiter, int numberOfFields, int headerLines)
        {
            mHeaderLines = headerLines;
            mRecordClassName = className;
            mDelimiter = delimiter;
            mNumberOfFields = numberOfFields;
        }

        /// <summary>Create a CSV Wrapper using the specified sample file with their headers.</summary>
        /// <param name="className">The name of the record class</param>
        /// <param name="delimiter">The delimiter for each field</param>
        /// <param name="sampleFile">A sample file with a header that contains the names of the fields.</param>
        public CsvOptions(string className, char delimiter, string sampleFile)
        {
            mRecordClassName = className;
            mDelimiter = delimiter;
            mSampleFileName = sampleFile;
        }

        /// <summary>Create a CSV Wrapper using the specified sample file with their headers.</summary>
        /// <param name="className">The name of the record class</param>
        /// <param name="delimiter">The delimiter for each field</param>
        /// <param name="sampleFile">A sample file with a header that contains the names of the fields.</param>
        /// <param name="headerDelimiter">The delimiter for the header line</param>
        public CsvOptions(string className, char delimiter, char headerDelimiter, string sampleFile)
        {
            mHeaderDelimiter = headerDelimiter;
            mRecordClassName = className;
            mDelimiter = delimiter;
            mSampleFileName = sampleFile;
        }

        private string mSampleFileName = string.Empty;
        private char mDelimiter = ',';
        private char mHeaderDelimiter = char.MinValue;
        private int mHeaderLines = 1;
        private string mRecordClassName = string.Empty;
        private int mNumberOfFields = -1;
        private string mFieldsPrefix = "Field_";
        private string mDateFormat = "dd/MM/yyyy";
        private string mDecimalSeparator = ".";
        private Encoding mEncoding = Encoding.GetEncoding(0);
        private bool mIgnoreEmptyLines = false;
        private bool mIncludeHeaderNames;

        /// <summary>A sample file from where to read the field names and number.</summary>
        public string SampleFileName
        {
            get { return mSampleFileName; }
            set { mSampleFileName = value; }
        }

        /// <summary>The delimiter for each field.</summary>
        public char Delimiter
        {
            get { return mDelimiter; }
            set { mDelimiter = value; }
        }

        /// <summary>The delimiter for each file name in the header.</summary>
        public char HeaderDelimiter
        {
            get { return mHeaderDelimiter; }
            set { mHeaderDelimiter = value; }
        }

        /// <summary>The name used for the record class (a valid .NET class).</summary>
        public string RecordClassName
        {
            get { return mRecordClassName; }
            set { mRecordClassName = value; }
        }

        /// <summary>The prefix used when you only specified the number of fields</summary>
        public string FieldsPrefix
        {
            get { return mFieldsPrefix; }
            set { mFieldsPrefix = StringHelper.ToValidIdentifier(value); }
        }

        /// <summary>The number of fields that the file contains.</summary>
        public int NumberOfFields
        {
            get { return mNumberOfFields; }
            set { mNumberOfFields = value; }
        }

        /// <summary>The number of header lines</summary>
        public int HeaderLines
        {
            get { return mHeaderLines; }
            set { mHeaderLines = value; }
        }

        /// <summary> 
        /// If True, add to the first row the names of the columns taken from DataTable and 
        /// also update the value of HeaderLines option to 1 
        /// </summary> 
        public bool IncludeHeaderNames
        {
            get { return mIncludeHeaderNames; }
            set
            {
                mIncludeHeaderNames = value;
                if (value && HeaderLines == 0)
                {
                    HeaderLines = 1;
                }
            }

        }

        /// <summary>The DateFormat used to read and write DateTime values</summary>
        public string DateFormat
        {
            get { return mDateFormat; }
            set { mDateFormat = value; }
        }

        /// <summary>The Decimal Separator used to read and write doubles, singles and decimal values</summary>
        public string DecimalSeparator
        {
            get { return mDecimalSeparator; }
            set { mDecimalSeparator = value; }
        }

        /// <summary>
        /// Encoding used when handling the CSV files.
        /// </summary>
        public Encoding Encoding
        {
            get { return mEncoding; }
            set { mEncoding = value; }
        }

        /// <summary>Should blank lines in the source file be left out of the final result?</summary>
        public bool IgnoreEmptyLines
        {
            get { return mIgnoreEmptyLines; }
            set { mIgnoreEmptyLines = value; }
        }

        private ConvertHelpers.DecimalConverter mDecimalConv;
        private ConvertHelpers.DoubleConverter mDoubleConv;
        private ConvertHelpers.SingleConverter mSingleConv;
        private ConvertHelpers.DateTimeConverter mDateConv;

        /// <summary>
        /// Convert a field to a string
        /// </summary>
        /// <param name="o">object we want to convert</param>
        /// <returns>string representation of the string</returns>
        internal string ValueToString(object o)
        {
            if (mDecimalConv == null) {
                mDecimalConv = new ConvertHelpers.DecimalConverter(DecimalSeparator);
                mDoubleConv = new ConvertHelpers.DoubleConverter(DecimalSeparator);
                mSingleConv = new ConvertHelpers.SingleConverter(DecimalSeparator);
                mDateConv = new ConvertHelpers.DateTimeConverter(DateFormat);
            }

            if (o == null)
                return string.Empty;
            else if (o is DateTime)
                return mDateConv.FieldToString(o);
            else if (o is Decimal)
                return mDecimalConv.FieldToString(o);
            else if (o is Double)
                return mDoubleConv.FieldToString(o);
            else if (o is Single)
                return mSingleConv.FieldToString(o);
            else
                return o.ToString();
        }
    }
}